Please refer to FIG. 1, which shows a conventional USB plug in use, i.e. the technology disclosed in the Taiwan Patent No. M249297. FIG. 1 shows that a USB plug 2 is inserted into a USB socket 1. The USB socket 1 includes a case 10 and a tongue piece 12 disposed in the case 10. When the USB plug 2 is inserted into the USB socket 1, the tongue piece 12 and the USB plug 2 are mutually connected via their respective inner terminals (not shown). FIG. 1 shows that the USB plug 2 is successfully inserted into the USB socket 1 and the electrical connection therebetween is actuated, wherein a top 2T of the USB plug 2 urges against the tongue piece 12, a bottom 2B of the USB plug 2 urges against the case 10, and two sides of the top 2T of the USB plug 2 respectively extend upward to form two guiding plates 21. When the USB plug 2 is inserted into the USB socket 1, the guiding plates 21 are located in the gaps between the tongue piece 12 and the case 10. The feature of the mentioned patent is to remove the case of the conventional USB plug to reduce the overall thickness thereof, thereby achieving the thinning effect. Besides, if the USB plug 2 is inserted into the USB socket 1 upside down, the guiding plates 21 will interfere with the case 10, which disables the USB plug 2 from being inserted into the USB socket 1. However, in practice, since the case of the USB plug 2 is made of plastics, it will be worn out after many times of use, especially the bottom 2B of the USB plug 2. Therefore, the thickness of the USB plug 2 will be thinner and thinner after many times of use. Besides, since the guiding plates 21 are protrusive, they not only are easy to collide with the case 10 and the tongue piece 12 of the USB socket 1 during the insertion, but also are easy to collide with other objects when not used. Moreover, since the case of the USB plug 2 is made of plastics, it will be easier to be deformed, broken or worn out during collision. Based on the above, the height of the guiding plates 21 of the USB plug 2 will be lowered and the bottom 2B of the USB plug 2 will be worn out after many times of use. This makes the overall thickness of the USB plug 2 thinner. That is, the thinned USB plug 2 will be easier to be inserted into the USB socket 1 upside down, i.e. the erroneous insertion will occur, and the foolproof effect is inactive. Additionally, even if the USB plug 2 is not worn out, the size of the USB socket 1 will change after many times of insertion and pull, especially the tongue piece 12. Since the tongue piece 12 is only a circuit board rather than an element with a high mechanical strength, it may slant upward after many times of insertion and pull. That is, the upper edge of the tongue piece 12 will be closer to the case 10, and relatively the lower edge of the tongue piece 12 will be farther from the case 10. This enlarges the space for containing the USB plug 2, which may enable the USB plug 2 to be inserted into the USB socket 1 upside down, and the foolproof effect is inactive. That is why the conventional USB plug 2 of FIG. 1 does not use the metal material. Due to the thinning design, element deformation and size change, the chance of inserting the USB plug 2 into the USB socket 1 upside down is greatly increased. Once the USB plug with a metal case is inserted into the USB socket 1 upside down, it will be electrically connected to the terminal in the tongue piece 12 to cause a short circuit. Hence, it is necessary to use the plastics, which are bad conductors, to manufacture the case of the USB plug 2. However, the above-mentioned issues will be generated by using the plastic case. Therefore, the conventional USB plug 2 of FIG. 1 is not practical.
Please refer to FIG. 2, which shows another conventional USB plug, i.e. the technology disclosed in the Taiwan Patent No. 1288315. The USB plug 2′ includes a case 2′a, and a supporting board 2′b is disposed in the case 2′a. A plurality of terminals 2′b1 are disposed on the supporting board 2′b, and a connecting mezzanine 2's is formed between the supporting board 2′b and the case 2′a. Based on the above, the USB plug 2′ is a quite common USB plug. However, the USB plug 2′ further has a plurality of electronic elements 2′c disposed at the lower face of the supporting board 2′b for sufficiently utilizing the space.
However, the disadvantage of the USB plug 2′ of FIG. 2 is that it uses the case 2′a which entirely covers the supporting board 2′b. Accordingly, when the supporting board 2′b is installed into the case 2′a, it cannot be inspected anymore. In this situation, it is impossible to determine whether the terminals 2′b1 on the supporting board 2′b are deficient or rusty, or the supporting board 2′b is slanting. Similarly, it is impossible to inspect whether the electronic elements 2′c at the lower face of the supporting board 2′b have defects. Therefore, the conventional USB plug 2′ of FIG. 2 has the disadvantage of low yield rate, which is a potential crisis for the credit of the company.
In order to overcome the drawbacks in the prior art, a USB wireless connection port is provided. The particular design in the present invention not only solves the problems described above, but also is easy to be implemented. Thus, the present invention has the utility for the industry.